The present invention relates to screw presses. More specifically, the present invention is concerned with a screw press provided with a rear excess fluid outlet.
Screw presses are well known in the art. They are conventionally used for removing soluble and dispersible materials from products, for example, excess fluid from paper pulp. It is to be noted that, for concision purposes, the example of the paper pulp will be used throughout the present disclosure. This should not be construed as a limitation of the present invention.
The principle of operation of conventional screw presses is believed to be well known to those skilled in the art and will therefore only be briefly described herein.
A screw press is basically an endless screw provided with a conical shaft that compresses the pulp as it moves from an inlet to an outlet. The endless screw is enclosed in a body that is provided with a screened surface allowing the excess fluid to be expelled from the pulp.
The throughoutput of screw presses is usually controlled by the rotational speed of the endless screw. However, there are limits to this control since the rotational speed of the endless screw must be sufficiently slow to thereby allow the excess fluid to flow through the screened body. This is a drawback of the conventional screw presses since it lowers the efficiency of the unit by unduly limiting the top rotational speed of the endless screw.
An object of the present invention is therefore to provide an improved screw press capable of overcoming the drawback described above.
More specifically, in accordance with the present invention, there is provided a screw press for removing excess fluid from material comprising:
a generally tubular body having a meshed surface; said body having a material inlet provided near a proximate end thereof;
an endless screw mounted in said tubular body; said endless screw including a generally conical shaft and a helicoidal blade mounted to said shaft; and
a rear excess fluid outlet provided in said proximate end of said tubular body.
Other objects, advantages and features of the present invention will become more apparent upon reading of the following non restrictive description of preferred embodiments thereof, given by way of example only with reference to the accompanying drawings.